Explosive train safety and arming system



Aug. 1, 1967 R. L. WAGNER ETAL 3,

EXPLOSIVE TRAIN SAFETY AND ARMING SYSTEM I Filed May 26, 1965 FIG. I.

FIG.2.

INVENTORS ROBERT L. WAGNER DONALD E. sazcgg M ATTORNEY-S United StatesPatent 3,333,541 EXPLOSIVE TRAIN SAFETY AND ARMING SYSTEM Robert L.Wagner and Donald E. Seeger, Sparta, N.J., as-

signors to the United States of America as represented by the Secretaryof the Army Filed May 26, 1965, Ser. N 0. 459,133 6 Claims. (Cl. 102-79)The invention described herein may be manufactured and used by or forthe Government for governmental purposes without the payment to us ofany royalty thereon.

This invention relates to an explosive train safety and arming systemfor use in munitions.

In most high explosive fuzing systems it is desirable for safetypurposes to employ some mechanism for mecham'cally separating the moresensitive components from the rest of the explosive train until suchtime as it is desirable to arm the fuze. Many systems have been devisedto accomplish this function. Generally, resort is made to rotors orsliding bars which house the sensitive components and which rotates ortranslates to position the explosive trains as desired. Inherently thesesystems contain gaps between the explosive components in the armedposition. These gaps or discontinuities create problems in assuringreliable propagation of the explosive train. To overcome these problemsexplosive components are made sufliciently large for a propagated flameor detonation wave to jump the gap. Because of the explosive powerinherent in such large components the surrounding environment mustnecessarily be designed to contain the explosive propagation until itreaches the main charge of the projectile. When considering a givencaliber projectile, structural limitations are quickly reached withregard to particular explosive trains.

The above problems become pronounced when miniaturization of explosivetrains is required. Although some semi-miniaturization of explosivetrains has taken place in recent years these smaller trains operateon'the same concepts as the larger ones and contain all of .the.associated problems which have existed since the out-of-line systemshave become adopted as standard practice.

Accordingly, it is an object of this invention to provide an explosivetrain safety and arming system which eliminates gaps between theexplosive components when the system is in the armed condition.

Another object of this invention is to provide a system as above whichcan use smaller explosive components thereby enhancing miniaturization.

A further object of this invention is to provide a system as aforesaidwhich comprises essentially two layers of explosive separated by a bodyof nonexplosive barrier material which is removable by conventionalmeans, and a force producing means acting on the explosive layers tourge same into intimate contact when the barrier is removed.

Further objects of this invention will in part be obvious and will inpart appear hereinafter.

For a fuller understanding of the nature and objects of this invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings wherein:

FIG. 1 is a view in elevation, and partly in cross-section of anembodiment of this invention, showing also in phantom outline a typicalenvironment for this invention;

FIG. 2 is a view showing the inventive embodiment of FIG. 1 in an armedposition;

FIG. 3 is a View in elevation and partly in cross-section showinganother embodiment of the invention.

Referring to the drawings, in which like reference characters refer tolike parts throughout, and referring particularly to FIGS. 1 and 2, 10represents generally an explosive train arming and fuzing system set ina conventional munitions projectile 12, shown in phantom outline. Asillustrated in FIG. 1 the system is in the unarmed or safe condition.Two thin films of explosive 14 and 16 comprise an explosive train forinitiation of a main charge 18 of explosive. The explosive films 14 and16 may be conventional sheet explosive. One end of the explosive 14 isoperatively connected with a detonator 20 of conventional design andsuitable for a particular appli cation. The other end portion of theexplosive 14 is positioned above an end portion of the explosive film16.

These portions of the explosive films 14 and 16 are in fixed spacerelationship with each other and are separated by a barrier 22 composedof a body of material which is capable of interrupting propagation ofthe explosive 14 to the explosive 16. Experiments have shown that a bodyof aluminum 0.010 inch in thickness has the capability of interruptingpropagation from a film of PETN inch thick and /8 inch wide. Thinnerfilms of explosive would, however, permit thinner barriers.

It is preferable that arrangement of the end portions of the explosivefilms 14 and 16, and the barrier 22 be substantially coplanar with eachother, or in a sandwich type orientation. The reason for thisarrangement will become apparent further on in the course of the presentdescription. A helical coil spring 24 or other force producing meansabuts the film 14 at the end portion thereof which forms the upper layerof the sandwich. The spring acts to urge the film 14 downwardly, andthus keep the sandwich intact. v

The barrier 22 can be withdrawn from between the films 14 and 16 bymechanical systems, not shown, but common to the munitions fuze art. Forexample, spin, setback, or deceleration systems could be readily adaptedfor withdrawing the barrier 22, as those skilled in the art wouldclearly understand. Upon removal of the barrier 22 the spring 24 wouldurge the film 14 towards the film 16 and intimate contact therewith. Inthis orientation (see FIG. 2) the explosive train system 10 is armed.The

film 16 is operatively connected with the main charge 18 and anexplosive propagation initiated by the detonator 20 will eventuallyreach and cause the charge. 18 to be initiated.

The embodiment illustrated in FIG. 3 operates substantially as theembodimentof FIG. 1, but shows further how this inventive system can beminiaturized. Two small bodies of explosive 26 and 28 are arrangedsubstantially coaxially and are interrupted by a barrier 30 to form anexplosive train sandwich. A spring 32 urges the body 26 toward the body28 and will cause the bodies to intimately contact each other when thebarrier 30 is withdrawn. Means for withdrawing the barrier 30 is notshown but may comprise any of those commonly known systems mentionedabove. A detonator 34 operatively communicates with body 26 and a maincharge 36 operatively communicates with body 28. As in the previousembodiment when the barrier 30 is withdrawn an unimpeded explosive trainensues which will result in a propagation when initiated by thedetonator 34 which will eventually reach and cause main charge 36 to beinitiated.

Since certain changes may be made in the above system without departingfrom the scope of the invention herein involved, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

We claim:

1. In a projectile having a central axis of rotation, the combinationwith said projectile of an explosive train arming and fuzing systemcomprising detonator means;

a main charge including a first body of explosive;

a second body of explosive operatively communicating with said detonatormeans;

a third body of explosive operatively communicating with said maincharge;

a rigid body responsive to centrifugal force away from said central axisand positioned intermediate said second and third bodies in intimatecontact therewith, said rigid body maintaining said second and thirdbodies in spaced relationships with each other; and

spring means for urging said second and third bodies into intimatecontact with each other when said rigid body is removed by saidcentrifugal force.

2. The arrangement of claim 1 wherein said rigid body is metallic.

3. In a projectile having a central axis of rotation, the

combination with said projectile of an explosive train arming and fuzingsystem comprising detonator means;

a main charge including a first body of explosive;

a second body of sheet explosive operatively communicating at one endwith said detonator means;

a third body of sheet explosive operatively communicating at one endwith said main charge;

a rigid body responsive to centrifugal force away from said central axisand having surface portions interposed between and separable from saidsecond and third bodies and being in frictional engagement therewith,said rigid body normally retaining said second and third bodies in aspaced relationship with each other; and

means for urging said other end portions of said second and third bodiesinto intimate contact with each other when said rigid body is removedfrom between said second and third bodies, said means maintaining saidfrictional engagement until a predetermined centrifugal force removessaid rigid body.

4. The arrangement as defined in claim 3 wherein said rigid body ismetallic.

5. In a projectile having a central axis of rotation, the

combination with said projectile of an explosive train arming and fuzingsystem comprising,

a rigid body responsive to centrifugal force away from said centralaxis, said body having surface portions interposed between and separablefrom said other end portions and being in intimate contact therewith,said rigid body normally retaining said other end portions of saidsecond and third bodies in a spaced relationship with each other; and

means for urging said other end portions of said second and third bodiesinto intimate contact with each other when said rigid body is removedfrom between said other end portions by a predetermined amount ofcentrifugal force.

6. In a projectile spinning about a central axis, the combination withsaid projectile of an explosive train arming and fuzing systemcomprising,

detonator means,

a main charge including a first body of explosive,

a second body of sheet explosive operatively communicating at one endwith said detonator means,

a third body of sheet explosive operatively communicating at one endwith said main charge, one of said other end portions of said second andthird bodies overlying the other,

a rigid body responsive to centrifugal force outward from said centralaxis, said body having surface portions interposed between and separablefrom said other end portions and being held in frictional en gagementtherewith, said rigid body normally retaining said other end portions ofsaid second and third bodies in a spaced relationship with each other;and

means for urging said other end portions of said second and third bodiesinto intimate contact with each other when said rigid body is removedfrom between said other end portions, said means maintaining saidfrictional engagement until a predetermined centrifugal force removessaid rigid body.

References Cited UNITED STATES PATENTS 1,325,758 12/1919 Semple 102-801,336,391 4/1920 Semple 102-79 1,372,582 3/1921 Weiser 10280 2,458,4681/ 1949 Flett 1027O 3,015,275 1/1962 Peyton et al 10270 FOREIGN PATENTS111,161 11/1917 Great Britain.

BENJAMIN A. BORCHELT, Primary Examiner.

SAMUEL FEINBERG, Examiner. G. H. GLANZMAN, Assistant Examiner.

1. IN A PROJECTILE HAVING A CENTRAL AXIS OF ROTATION, THE COMBINATIONWITH SAID PROJECTILE OF AN EXPLOSIVE TRAIN ARMING AND FUZING SYSTEMCOMPRISING DETONATOR MEANS; A MAIN CHARGE INCLUDING A FIRST BODY OFEXPLOSIVE; A SECOND BODY OF EXPLOSIVE OPERATIVELY COMMUNICATING WITHSAID DETONATOR MEANS; A THIRD BODY OF EXPLOSIVE OPERATIVELYCOMMUNICATING WITH SAID MAIN CHARGE; A RIGID BODY RESPONSIVE TOCENTRIFUGAL FORCE AWAY FROM SAID CENTRAL AXIS AND POSITIONEDINTERMEDIATE SAID SECOND AND THIRD BODIES IN INTIMATE CONTACT THEREWITH,SAID RIGID BODY MAINTAINING SAID SECOND AND THIRD BODIES IN SPACEDRELATIONSHIPS WITH EACH OTHER; AND SPRING MEANS FOR URGING SAID SECONDAND THIRD BODIES INTO INTIMATE CONTACT WITH EACH OTHER WHEN SAID RIGIDBODY IS REMOVED BY SAID CENTRIFUGAL FORCE.